The present invention is directed to an improvement in tape transporting apparatuses modified to ensure stable running while preventing damage to tapes of varying thickness in all operating modes, including loading and unloading of the tape.
A conventional tape transporting apparatus 300 is illustrated in FIG. 14. A tape 4 is initially drawn out from a cassette 1 and wound around a cylinder 5 by inclined posts 8 and 9, guide posts 10, 11, 12, and 15, and a tension regulator post 13. The cassette 1 accommodates two reels, a supply reel 2 and a take-up reel 3. After loading, the movement of the tape 4 is controlled by the rotation of a capstan 6, which moves the tape out from the supply reel 2, between the capstan 6 and a pinch roller 7, and into the take-up reel 3. When the tape transporting apparatus 300 operates in play or record mode, the tape 4 has a relatively low tension which is maintained by the guide posts 10, 11, 12, and 15 that stabilize the travelling height of the tape 4 and by the tension regulator post 13 that adjusts the load torque of the feed reel 2.
However, when the tape 4 travels in the reverse direction, as in the rewind mode, the tension regulator post 13 is inactive and the take-up torque exerted on the tape 4 is constant. As a result, the tension in the tape varies significantly, depending on the winding diameter of the tape on the reel taking up the tape. When the winding diameter is small, the tension in the tape 4 is high, increasing the likelihood that the guide posts will cause damage to the tape.
The prior art addresses this problem by setting the guide posts to provide a broader range of running heights available to the tape, thus exerting less pressure on the tape. This decreases the likelihood that the guide posts will damage the tape when the tension in the tape is high, such as when the tape transporting apparatus is in rewind mode.
When the tension in the tape is high, the concern is to prevent damage to the tape. Conversely, when the tension in the tape is low, the likelihood that the guide posts will damage the tape is low, but the tension in the tape may be insufficient to keep the tape at a stable travelling height. Thus, the concern is to set the guide posts to sufficiently narrow the range of travelling heights available to the tape to provide enough guidance to the tape to ensure stable travelling.
While the prior art may prevent damage to the tape when the tension in the tape is high by increasing the range of available travelling heights, the prior art does not always provide sufficient guidance to the travelling height of the tape when the tension in the tape is low, such as when the tape transporting apparatus is in play or record mode. Consequently, the reproduction envelope is not stabilized and travelling of the tape is unstable. Moreover, with technological advances, tapes have become thinner, and may not have the strength to withstand even the less constricting pressure exerted by the guide posts provided by current tape transporting apparatuses.
As can be seen, the prior art tape transporting apparatuses provide some protection against damaging tapes when the tape tension is high. Nevertheless, none of these devices adjust the guidance given to a tape to the tension in the tape at a particular time, which provides the important advantage of ensuring stable operation as well as preventing damage to the tape. The current invention also prevents damage to the tape while the tape is being loaded and unloaded. An additional advantage achieved by the current invention is the capability of the tape transporting apparatuses to safely handle very thin tapes.